1. Field of the Invention
The present invention relates to an in-vehicle speaker mounting structure for mounting a speaker on a vehicle such as an automobile.
2. Description of the Related Art
Conventionally, speakers for outputting sound reproduced by an in-vehicle audio system represented by such as an in-vehicle radio and an in-vehicle CD player are mounted on doors and/or a rear parcel shelf inside the passenger compartment of an automobile. A general mounting structure for mounting such speakers on an automobile will be described below with reference to FIG. 22.
FIG. 22 illustrates an example of a conventional in-vehicle speaker mounting structure and shows a case where a speaker unit 120 is mounted on a door panel 104 of an automobile. An opening 105 is formed in the door panel 104 for mounting the speaker unit 120 thereon, and four set holes 119 are formed around this opening 105.
A grommet 102 into which a screw 103 is screwed is fit in each set hole 119.
When mounting this speaker unit 120 on the door panel 104 (hereinafter, this work is also referred to simply as “mounting work”), an operator aligns screw holes 120a formed in the speaker unit 120 with the grommets 102 installed in the set holes 119, and passes screws 103 through the screw holes 120a for screwing into the grommets 102 while holding a state in which the speaker unit 120 is disposed in the opening 105.
According to the conventional in-vehicle speaker mounting structure, troublesome and complicated operations are needed to mount the speakers on the vehicle body, resulting in an increase in man-hours for operations.
There have been proposed in-vehicle speaker rotational mounting structures, and one example is disclosed in JP-A-2001-169374.
In the technique disclosed in the JP-A-2001-169374, a speaker unit 101 is fixed to a speaker unit mounting plate 160 as shown in FIG. 23. Namely, when mounting the speaker unit 101 on the speaker unit mounting plate 160, the speaker unit 101 is inserted into a mounting opening 170 from a front side of the speaker unit mounting plate 160. As this occurs, engagement pieces 140 protruding from a plurality of locations on a rear side of the speaker unit 101 and an abutment piece 150 also protruding from a single location on the rear side of the speaker unit 101 are inserted into engagement piece inserting cut-outs 180a and an abutment piece inserting cut-out 190a which are all formed in the speaker unit mounting plate 160, respectively.
Then, in this state, the speaker unit 101 is rotated in a direction indicated by an arrow Z. As a result, the respective engagement pieces 140 are guided along inclined portions 180b for engagement with engagement piece engagement portions 180c, respectively, whereby the speaker unit 101 is fixed to the speaker unit mounting plate 160.
In addition, as a result of the rotation of the speaker unit 101 in the direction indicated by the arrow Z, the abutment piece 150 moves from the abutment piece inserting cut-out 190a to an abutment piece locking cut-out 190b for engagement therewith via a locking portion 190c which is a stepped portion. Thus, even when the speaker unit is attempted to be rotated in a reverse direction (a direction reverse to the direction indicated by the arrow Z), the abutment piece 150 comes into abutment with the locking portion 190c to thereby prohibit the reverse rotation of the speaker unit 101.
With the rotational-mount type speaker disclosed in the JP-A-2001-169374, however, in order to prevent the ingress of rain water and/or dust into the interior of the speaker unit 101 and an inner part of a door panel 201 from a gap between the speaker unit 101 and the door panel 201, a tight adhesion needs to be provided between the speaker unit 101 and the door panel 201 to provide waterproof and dust proof functions. This requires a strong torque to be applied to the speaker unit 101 when the speaker is mounted on the vehicle body.
In this case, although it is not impossible for workers to manually rotate the speaker unit 101, on production lines for mass production, speaker units 101 have to be mounted on a number of automobiles, and this has caused a problem that the manual mounting work of speakers forces the workers to bear tremendously excessive work load.